Network system, management device, and management method

Abstract

A network system includes a plurality of transmission devices, each of which being provided with a wavelength selective switch including a wavelength filter, configured to transmit an optical signal for each channel; and a management device configured to manage the plurality of transmission devices. The wavelength selective switch configured to enable band setting that widens a transmission band of an optical signal of a predetermined channel to the wavelength filter of an adjacent channel. The management device is further configured to calculate an OSNR of the optical signal based on power loss, calculate a bandwidth of the optical signal according to narrowing due to the wavelength filter, determine whether or not the OSNR and the bandwidth respectively satisfies a condition of transmission quality of the optical signal, and decide whether or not to cause the wavelength selective switch to perform the band setting based on a result of the determination.

What is claimed is: 
     
       1. A network system comprising:
 a plurality of transmission devices, each of which being provided with a wavelength selective switch including a wavelength filter, configured to transmit an optical signal for each channel; and 
 a management device configured to manage the plurality of transmission devices, wherein 
 the wavelength selective switch configured to enable band setting that widens a transmission band of an optical signal of a predetermined channel to the wavelength filter of an adjacent channel, 
 the management device is further configured to:
 calculate an OSNR of the optical signal of the predetermined channel based on power loss due to the wavelength filter over a path of the optical signal of the predetermined channel; 
 calculate a bandwidth of the optical signal of the predetermined channel according to narrowing due to the wavelength filter over the path; 
 determine whether or not the OSNR and the bandwidth respectively satisfies a condition of transmission quality of the optical signal of the predetermined channel; and 
 decide whether or not to cause the wavelength selective switch to perform the band setting based on a result of the determination. 
 
 
     
     
       2. The network system according to  claim 1 , wherein
 the management device is configured to, when the bandwidth out of the OSNR and the bandwidth when the transmission band of the optical signal of the predetermined channel is not widened does not satisfy the condition of the transmission quality, decide to perform the band setting when the OSNR and the bandwidth when the transmission band of the optical signal of the predetermined channel is widened respectively satisfies the condition of the transmission quality. 
 
     
     
       3. The network system according to  claim 1 , wherein
 the management device is configured to, when the OSNR and the bandwidth in a case where the transmission band of the optical signal of the predetermined channel is not widened respectively satisfies the condition of the transmission quality, decide not to perform the band setting. 
 
     
     
       4. The network system according to  claim 1 , wherein the management device is further configured to:
 make a determination using the condition of the transmission quality according to a combination of a multilevel degree of modulation and a baud rate of the optical signal of the predetermined channel; and 
 decide to set the combination of the multilevel degree of modulation and the baud rate in a case where the OSNR and the bandwidth respectively satisfies the condition of the transmission quality in the optical signal of the predetermined channel. 
 
     
     
       5. The network system according to  claim 1 , wherein the management device is further configured to:
 calculate the OSNR in accordance with a widening of the transmission band due to the band setting; 
 calculate the bandwidth in accordance with widening of the transmission band due to the band setting; and 
 make a decision to set widening of the transmission band of the optical signal of the predetermined channel in the wavelength selective switch in a case where the OSNR and the bandwidth respectively satisfies the condition of the transmission quality of the optical signal of the predetermined channel. 
 
     
     
       6. The network system according to  claim 1 , wherein
 in the wavelength selective switch, when the band setting is performed, the transmission band of the optical signal of the predetermined channel is widened and the power loss of the optical signal of the predetermined channel is increased. 
 
     
     
       7. The network system according to  claim 1 , wherein the wavelength selective switch is configured to:
 include a mirror array for each channel which functions as the wavelength filter and is arranged in a first direction, and a plurality of ports onto which an optical signal reflected by the mirror array is incident; and 
 when the band setting is performed, control angles of mirrors of a first region and mirrors of a second region to different values so that optical signals are incident on different ports of the plurality of ports from the mirrors of the first region and the mirrors of the second region, which are obtained by dividing the mirror array by a ratio of 1:1 in a second direction perpendicular to the first direction. 
 
     
     
       8. A management device comprising:
 a memory; and 
 a processor coupled to the memory and configured to control a plurality of transmission devices, each of which being provided with a wavelength selective switch including a wavelength filter that transmits an optical signal for each channel, the wavelength selective switch enabling band setting that widens a transmission band of an optical signal of a predetermined channel to the wavelength filter of an adjacent channel, 
 wherein the processor is further configured to:
 calculate an OSNR of the optical signal of the predetermined channel based on power loss due to the wavelength filter over a path of the optical signal of the predetermined channel; 
 calculate a bandwidth of the optical signal of the predetermined channel according to narrowing due to the wavelength filter over the path; 
 determine whether or not the OSNR and the bandwidth respectively satisfies a condition of transmission quality of the optical signal of the predetermined channel; and 
 decide whether or not to cause the wavelength selective switch perform the band setting based on a result of the determination. 
 
 
     
     
       9. A management method of a management device for managing a plurality of transmission devices, comprising:
 calculating an OSNR of an optical signal of a predetermined channel based on power loss due to a wavelength filter over a path of the optical signal of the predetermined channel, the wavelength filter transmitting an optical signal for each channel and being included in a wavelength selective switch provided in each of the plurality of transmission devices, the wavelength selective switch enabling band setting that widens a transmission band of the optical signal of a predetermined channel to the wavelength filter of an adjacent channel; 
 calculating a bandwidth of the optical signal of the predetermined channel according to narrowing due to the wavelength filter over the path; 
 determining whether or not the OSNR and the bandwidth respectively satisfies the condition of transmission quality of the optical signal of the predetermined channel; and 
 deciding whether or not to cause the wavelength selective switch to perform the band setting based on a result of the determining.